Mastering tactical motifs : r/chess

Daily Chess Tactics Training - Vol.4

Just broke 1900 on chesstempo! Started playing 15 months ago and this resource has been extremely beneficial and I would credit as one of the biggest factors in my chess growth. Results

Chesstempo.com now has an opening trainer : r/chess

Perfect Chess Trainer – Apps on Google Play

PDF) Assessing the difficulty of chess tactical problems

Grandmaster Guide to learn and improve chess tactics

Top 7 Best Chess Tools to Skyrocket Your Chess

Chess Tactics Puzzle Training: ChessTempo Tactics training session

Improve Your Chess Tactics: 700 Practical Lessons & Exercises

Tactics training on Chessity with live commentary!